SlideShare a Scribd company logo
Hard times to come. There are not
simple groups of order 2016. [Scott,
Ex.10.7.13.]
Proof. Let G be a simple groupof order 2016.
Along the lines of the analogue statement for
1008, 10.7.5. in Scott. Let n7 be the number of 7-
Sylow subgroups P. One has that n7=8,36 or 288
by Sylow (must divide 288 and congruent to 1
mod 7). If n7=8 then 3 divides |C(P)| so there is
an element of order 21 which is impossible in the
symmetric group S8.
Let n7=36, |N(P)|=56, N/C embeds into Aut(P) of
order 6 hence |C(P)|=28. There is an element of
order 2 in C(P) hence also an element x in C(P) of
order 14. By 10.2.10 in the faithful representation on
N(P) of degree 36, x^2 is of cycle type 1-7-7-7-7-7
so x has type 1-14-14-7 and Ch(x^7)=8. If y is in
N(P) - C(P) then by 10.2.11 Ch(y)<=6 and x and y
are not conjugates. We conclude that all conjugates
by elements in N(P) of involutions in C(P) remain in
C(P).
Let a be an involution in C(P) and denote by f(a) the order of
Cl_N(P)(a). Appplying 10.7.4, |Cl_G(a)|=36*f(a)/8 hence f(a)
must be even. A group of order 28 is either abelian of type
C28 or C2xC2xC7, or nonabelian either dihedral or the
extension of C14 by C4 with amalgamation. C(P) must be
abelian as P is central, which is the case neither in D14 nor
in the extension of C14 by C4 with amalgamation. If C(P) is
Abelian of type C28 then there is only one involution which is
impossible. If C(P) is Abelian of type C2xC2xC7 then there
are 3 involutions of which necessarily at least one is central
in N(P) as N/C is of order 2, which is again impossible.
There remained the case n7=288. In this case G is
Frobenius. Indeed, P is such that P ∩ P^g is the
identity subgroup for every g in G − P. Then also
the Frobenius kernel of order 288 is nilpotent,
and both Sylow for 2,3 are also normal. The proof
is complete.
In spite of this uneasy fact, prosperous new year to
all at LinkedIn and the StackExchange.

More Related Content

What's hot

Galois theory
Galois theoryGalois theory
Galois theory
shinojmadhu
 
Substitution codes
Substitution codesSubstitution codes
Substitution codes
harlie90
 
0808 ch 8 day 8
0808 ch 8 day 80808 ch 8 day 8
0808 ch 8 day 8
festivalelmo
 
On sum edge coloring of regular, bipartite and split graphs
On sum edge coloring of regular,  bipartite and split graphsOn sum edge coloring of regular,  bipartite and split graphs
On sum edge coloring of regular, bipartite and split graphs
政謙 陳
 
1 s2.0-0012365 x81900017-main
1 s2.0-0012365 x81900017-main1 s2.0-0012365 x81900017-main
1 s2.0-0012365 x81900017-main
Bala Krishna
 
On the equality of the grundy numbers of a graph
On the equality of the grundy numbers of a graphOn the equality of the grundy numbers of a graph
On the equality of the grundy numbers of a graph
ijngnjournal
 
3D Geometry QA 9
3D Geometry QA 93D Geometry QA 9
3D Geometry QA 9
Lakshmikanta Satapathy
 
Enumeration of 2-level polytopes
Enumeration of 2-level polytopesEnumeration of 2-level polytopes
Enumeration of 2-level polytopes
Vissarion Fisikopoulos
 
Galois theory andrew hubery
Galois theory andrew huberyGalois theory andrew hubery
Galois theory andrew hubery
THANASIS TZIASTAS
 
FCA GCSE changing the subject
FCA GCSE changing the subject FCA GCSE changing the subject
FCA GCSE changing the subject
Miss_Cowell
 
Algebraic from
Algebraic fromAlgebraic from
Algebraic from
fannybae
 
Algorithum Analysis
Algorithum AnalysisAlgorithum Analysis
Algorithum Analysis
Ain-ul-Moiz Khawaja
 
Cs6702 graph theory and applications Anna University question paper apr may 2...
Cs6702 graph theory and applications Anna University question paper apr may 2...Cs6702 graph theory and applications Anna University question paper apr may 2...
Cs6702 graph theory and applications Anna University question paper apr may 2...
appasami
 
Basic galois field arithmatics required for error control codes
Basic galois field arithmatics required for error control codesBasic galois field arithmatics required for error control codes
Basic galois field arithmatics required for error control codes
Madhumita Tamhane
 
A note on arithmetic progressions in sets of integers
A note on arithmetic progressions in sets of integersA note on arithmetic progressions in sets of integers
A note on arithmetic progressions in sets of integers
Lukas Nabergall
 
Asymptotic notation
Asymptotic notationAsymptotic notation
Asymptotic notation
Saranya Natarajan
 
lecture 4
lecture 4lecture 4
lecture 4
sajinsc
 
Master method theorem
Master method theoremMaster method theorem
Master method theorem
Rajendran
 
A Note on TopicRNN
A Note on TopicRNNA Note on TopicRNN
A Note on TopicRNN
Tomonari Masada
 
A Note on Latent LSTM Allocation
A Note on Latent LSTM AllocationA Note on Latent LSTM Allocation
A Note on Latent LSTM Allocation
Tomonari Masada
 

What's hot (20)

Galois theory
Galois theoryGalois theory
Galois theory
 
Substitution codes
Substitution codesSubstitution codes
Substitution codes
 
0808 ch 8 day 8
0808 ch 8 day 80808 ch 8 day 8
0808 ch 8 day 8
 
On sum edge coloring of regular, bipartite and split graphs
On sum edge coloring of regular,  bipartite and split graphsOn sum edge coloring of regular,  bipartite and split graphs
On sum edge coloring of regular, bipartite and split graphs
 
1 s2.0-0012365 x81900017-main
1 s2.0-0012365 x81900017-main1 s2.0-0012365 x81900017-main
1 s2.0-0012365 x81900017-main
 
On the equality of the grundy numbers of a graph
On the equality of the grundy numbers of a graphOn the equality of the grundy numbers of a graph
On the equality of the grundy numbers of a graph
 
3D Geometry QA 9
3D Geometry QA 93D Geometry QA 9
3D Geometry QA 9
 
Enumeration of 2-level polytopes
Enumeration of 2-level polytopesEnumeration of 2-level polytopes
Enumeration of 2-level polytopes
 
Galois theory andrew hubery
Galois theory andrew huberyGalois theory andrew hubery
Galois theory andrew hubery
 
FCA GCSE changing the subject
FCA GCSE changing the subject FCA GCSE changing the subject
FCA GCSE changing the subject
 
Algebraic from
Algebraic fromAlgebraic from
Algebraic from
 
Algorithum Analysis
Algorithum AnalysisAlgorithum Analysis
Algorithum Analysis
 
Cs6702 graph theory and applications Anna University question paper apr may 2...
Cs6702 graph theory and applications Anna University question paper apr may 2...Cs6702 graph theory and applications Anna University question paper apr may 2...
Cs6702 graph theory and applications Anna University question paper apr may 2...
 
Basic galois field arithmatics required for error control codes
Basic galois field arithmatics required for error control codesBasic galois field arithmatics required for error control codes
Basic galois field arithmatics required for error control codes
 
A note on arithmetic progressions in sets of integers
A note on arithmetic progressions in sets of integersA note on arithmetic progressions in sets of integers
A note on arithmetic progressions in sets of integers
 
Asymptotic notation
Asymptotic notationAsymptotic notation
Asymptotic notation
 
lecture 4
lecture 4lecture 4
lecture 4
 
Master method theorem
Master method theoremMaster method theorem
Master method theorem
 
A Note on TopicRNN
A Note on TopicRNNA Note on TopicRNN
A Note on TopicRNN
 
A Note on Latent LSTM Allocation
A Note on Latent LSTM AllocationA Note on Latent LSTM Allocation
A Note on Latent LSTM Allocation
 

Similar to Hard times to come

Goldberg-Coxeter construction for 3- or 4-valent plane maps
Goldberg-Coxeter construction for 3- or 4-valent plane mapsGoldberg-Coxeter construction for 3- or 4-valent plane maps
Goldberg-Coxeter construction for 3- or 4-valent plane maps
Mathieu Dutour Sikiric
 
Solutions Manual for Mathematical Proofs A Transition to Advanced Mathematics...
Solutions Manual for Mathematical Proofs A Transition to Advanced Mathematics...Solutions Manual for Mathematical Proofs A Transition to Advanced Mathematics...
Solutions Manual for Mathematical Proofs A Transition to Advanced Mathematics...
riven058
 
Elliptic Curves
Elliptic CurvesElliptic Curves
Elliptic Curves
AlexanderWei11
 
Set
SetSet
Complex analysis notes
Complex analysis notesComplex analysis notes
Complex analysis notes
Prakash Dabhi
 
Polycycles and their elementary decompositions
Polycycles and their elementary decompositionsPolycycles and their elementary decompositions
Polycycles and their elementary decompositions
Mathieu Dutour Sikiric
 

Similar to Hard times to come (6)

Goldberg-Coxeter construction for 3- or 4-valent plane maps
Goldberg-Coxeter construction for 3- or 4-valent plane mapsGoldberg-Coxeter construction for 3- or 4-valent plane maps
Goldberg-Coxeter construction for 3- or 4-valent plane maps
 
Solutions Manual for Mathematical Proofs A Transition to Advanced Mathematics...
Solutions Manual for Mathematical Proofs A Transition to Advanced Mathematics...Solutions Manual for Mathematical Proofs A Transition to Advanced Mathematics...
Solutions Manual for Mathematical Proofs A Transition to Advanced Mathematics...
 
Elliptic Curves
Elliptic CurvesElliptic Curves
Elliptic Curves
 
Set
SetSet
Set
 
Complex analysis notes
Complex analysis notesComplex analysis notes
Complex analysis notes
 
Polycycles and their elementary decompositions
Polycycles and their elementary decompositionsPolycycles and their elementary decompositions
Polycycles and their elementary decompositions
 

More from János Kurdics

kurdics_epass
kurdics_epasskurdics_epass
kurdics_epass
János Kurdics
 
Braun Centenary
Braun CentenaryBraun Centenary
Braun Centenary
János Kurdics
 
AtinerICT18
AtinerICT18AtinerICT18
AtinerICT18
János Kurdics
 
Professor Ákos Császár
Professor Ákos CsászárProfessor Ákos Császár
Professor Ákos Császár
János Kurdics
 
International conference on global studies
International conference on global studiesInternational conference on global studies
International conference on global studies
János Kurdics
 
Kalman Rudolf dies at 86
Kalman Rudolf dies at 86Kalman Rudolf dies at 86
Kalman Rudolf dies at 86
János Kurdics
 
Research Trip To Poland
Research Trip To PolandResearch Trip To Poland
Research Trip To Poland
János Kurdics
 
Bialystok15
Bialystok15Bialystok15
Bialystok15
János Kurdics
 
robo
roborobo
nao12
nao12nao12
nao11
nao11nao11
seminartr_20151022
seminartr_20151022seminartr_20151022
seminartr_20151022
János Kurdics
 
978-3-659-62092-8_sample
978-3-659-62092-8_sample978-3-659-62092-8_sample
978-3-659-62092-8_sample
János Kurdics
 
resume_kurdics1
resume_kurdics1resume_kurdics1
resume_kurdics1
János Kurdics
 

More from János Kurdics (18)

kurdics_epass
kurdics_epasskurdics_epass
kurdics_epass
 
Braun Centenary
Braun CentenaryBraun Centenary
Braun Centenary
 
AtinerICT18
AtinerICT18AtinerICT18
AtinerICT18
 
Professor Ákos Császár
Professor Ákos CsászárProfessor Ákos Császár
Professor Ákos Császár
 
trans_kurdics
trans_kurdicstrans_kurdics
trans_kurdics
 
International conference on global studies
International conference on global studiesInternational conference on global studies
International conference on global studies
 
Kalman Rudolf dies at 86
Kalman Rudolf dies at 86Kalman Rudolf dies at 86
Kalman Rudolf dies at 86
 
Research Trip To Poland
Research Trip To PolandResearch Trip To Poland
Research Trip To Poland
 
robo16
robo16robo16
robo16
 
Bialystok15
Bialystok15Bialystok15
Bialystok15
 
kjatiner
kjatinerkjatiner
kjatiner
 
th_kurdics
th_kurdicsth_kurdics
th_kurdics
 
robo
roborobo
robo
 
nao12
nao12nao12
nao12
 
nao11
nao11nao11
nao11
 
seminartr_20151022
seminartr_20151022seminartr_20151022
seminartr_20151022
 
978-3-659-62092-8_sample
978-3-659-62092-8_sample978-3-659-62092-8_sample
978-3-659-62092-8_sample
 
resume_kurdics1
resume_kurdics1resume_kurdics1
resume_kurdics1
 

Recently uploaded

Travis Hills of MN is Making Clean Water Accessible to All Through High Flux ...
Travis Hills of MN is Making Clean Water Accessible to All Through High Flux ...Travis Hills of MN is Making Clean Water Accessible to All Through High Flux ...
Travis Hills of MN is Making Clean Water Accessible to All Through High Flux ...
Travis Hills MN
 
Direct Seeded Rice - Climate Smart Agriculture
Direct Seeded Rice - Climate Smart AgricultureDirect Seeded Rice - Climate Smart Agriculture
Direct Seeded Rice - Climate Smart Agriculture
International Food Policy Research Institute- South Asia Office
 
快速办理(UAM毕业证书)马德里自治大学毕业证学位证一模一样
快速办理(UAM毕业证书)马德里自治大学毕业证学位证一模一样快速办理(UAM毕业证书)马德里自治大学毕业证学位证一模一样
快速办理(UAM毕业证书)马德里自治大学毕业证学位证一模一样
hozt8xgk
 
Describing and Interpreting an Immersive Learning Case with the Immersion Cub...
Describing and Interpreting an Immersive Learning Case with the Immersion Cub...Describing and Interpreting an Immersive Learning Case with the Immersion Cub...
Describing and Interpreting an Immersive Learning Case with the Immersion Cub...
Leonel Morgado
 
GBSN - Biochemistry (Unit 6) Chemistry of Proteins
GBSN - Biochemistry (Unit 6) Chemistry of ProteinsGBSN - Biochemistry (Unit 6) Chemistry of Proteins
GBSN - Biochemistry (Unit 6) Chemistry of Proteins
Areesha Ahmad
 
Randomised Optimisation Algorithms in DAPHNE
Randomised Optimisation Algorithms in DAPHNERandomised Optimisation Algorithms in DAPHNE
Randomised Optimisation Algorithms in DAPHNE
University of Maribor
 
molar-distalization in orthodontics-seminar.pptx
molar-distalization in orthodontics-seminar.pptxmolar-distalization in orthodontics-seminar.pptx
molar-distalization in orthodontics-seminar.pptx
Anagha Prasad
 
Eukaryotic Transcription Presentation.pptx
Eukaryotic Transcription Presentation.pptxEukaryotic Transcription Presentation.pptx
Eukaryotic Transcription Presentation.pptx
RitabrataSarkar3
 
Farming systems analysis: what have we learnt?.pptx
Farming systems analysis: what have we learnt?.pptxFarming systems analysis: what have we learnt?.pptx
Farming systems analysis: what have we learnt?.pptx
Frédéric Baudron
 
8.Isolation of pure cultures and preservation of cultures.pdf
8.Isolation of pure cultures and preservation of cultures.pdf8.Isolation of pure cultures and preservation of cultures.pdf
8.Isolation of pure cultures and preservation of cultures.pdf
by6843629
 
Authoring a personal GPT for your research and practice: How we created the Q...
Authoring a personal GPT for your research and practice: How we created the Q...Authoring a personal GPT for your research and practice: How we created the Q...
Authoring a personal GPT for your research and practice: How we created the Q...
Leonel Morgado
 
Mending Clothing to Support Sustainable Fashion_CIMaR 2024.pdf
Mending Clothing to Support Sustainable Fashion_CIMaR 2024.pdfMending Clothing to Support Sustainable Fashion_CIMaR 2024.pdf
Mending Clothing to Support Sustainable Fashion_CIMaR 2024.pdf
Selcen Ozturkcan
 
EWOCS-I: The catalog of X-ray sources in Westerlund 1 from the Extended Weste...
EWOCS-I: The catalog of X-ray sources in Westerlund 1 from the Extended Weste...EWOCS-I: The catalog of X-ray sources in Westerlund 1 from the Extended Weste...
EWOCS-I: The catalog of X-ray sources in Westerlund 1 from the Extended Weste...
Sérgio Sacani
 
The binding of cosmological structures by massless topological defects
The binding of cosmological structures by massless topological defectsThe binding of cosmological structures by massless topological defects
The binding of cosmological structures by massless topological defects
Sérgio Sacani
 
AJAY KUMAR NIET GreNo Guava Project File.pdf
AJAY KUMAR NIET GreNo Guava Project File.pdfAJAY KUMAR NIET GreNo Guava Project File.pdf
AJAY KUMAR NIET GreNo Guava Project File.pdf
AJAY KUMAR
 
11.1 Role of physical biological in deterioration of grains.pdf
11.1 Role of physical biological in deterioration of grains.pdf11.1 Role of physical biological in deterioration of grains.pdf
11.1 Role of physical biological in deterioration of grains.pdf
PirithiRaju
 
(June 12, 2024) Webinar: Development of PET theranostics targeting the molecu...
(June 12, 2024) Webinar: Development of PET theranostics targeting the molecu...(June 12, 2024) Webinar: Development of PET theranostics targeting the molecu...
(June 12, 2024) Webinar: Development of PET theranostics targeting the molecu...
Scintica Instrumentation
 
Micronuclei test.M.sc.zoology.fisheries.
Micronuclei test.M.sc.zoology.fisheries.Micronuclei test.M.sc.zoology.fisheries.
Micronuclei test.M.sc.zoology.fisheries.
Aditi Bajpai
 
HOW DO ORGANISMS REPRODUCE?reproduction part 1
HOW DO ORGANISMS REPRODUCE?reproduction part 1HOW DO ORGANISMS REPRODUCE?reproduction part 1
HOW DO ORGANISMS REPRODUCE?reproduction part 1
Shashank Shekhar Pandey
 
Sexuality - Issues, Attitude and Behaviour - Applied Social Psychology - Psyc...
Sexuality - Issues, Attitude and Behaviour - Applied Social Psychology - Psyc...Sexuality - Issues, Attitude and Behaviour - Applied Social Psychology - Psyc...
Sexuality - Issues, Attitude and Behaviour - Applied Social Psychology - Psyc...
PsychoTech Services
 

Recently uploaded (20)

Travis Hills of MN is Making Clean Water Accessible to All Through High Flux ...
Travis Hills of MN is Making Clean Water Accessible to All Through High Flux ...Travis Hills of MN is Making Clean Water Accessible to All Through High Flux ...
Travis Hills of MN is Making Clean Water Accessible to All Through High Flux ...
 
Direct Seeded Rice - Climate Smart Agriculture
Direct Seeded Rice - Climate Smart AgricultureDirect Seeded Rice - Climate Smart Agriculture
Direct Seeded Rice - Climate Smart Agriculture
 
快速办理(UAM毕业证书)马德里自治大学毕业证学位证一模一样
快速办理(UAM毕业证书)马德里自治大学毕业证学位证一模一样快速办理(UAM毕业证书)马德里自治大学毕业证学位证一模一样
快速办理(UAM毕业证书)马德里自治大学毕业证学位证一模一样
 
Describing and Interpreting an Immersive Learning Case with the Immersion Cub...
Describing and Interpreting an Immersive Learning Case with the Immersion Cub...Describing and Interpreting an Immersive Learning Case with the Immersion Cub...
Describing and Interpreting an Immersive Learning Case with the Immersion Cub...
 
GBSN - Biochemistry (Unit 6) Chemistry of Proteins
GBSN - Biochemistry (Unit 6) Chemistry of ProteinsGBSN - Biochemistry (Unit 6) Chemistry of Proteins
GBSN - Biochemistry (Unit 6) Chemistry of Proteins
 
Randomised Optimisation Algorithms in DAPHNE
Randomised Optimisation Algorithms in DAPHNERandomised Optimisation Algorithms in DAPHNE
Randomised Optimisation Algorithms in DAPHNE
 
molar-distalization in orthodontics-seminar.pptx
molar-distalization in orthodontics-seminar.pptxmolar-distalization in orthodontics-seminar.pptx
molar-distalization in orthodontics-seminar.pptx
 
Eukaryotic Transcription Presentation.pptx
Eukaryotic Transcription Presentation.pptxEukaryotic Transcription Presentation.pptx
Eukaryotic Transcription Presentation.pptx
 
Farming systems analysis: what have we learnt?.pptx
Farming systems analysis: what have we learnt?.pptxFarming systems analysis: what have we learnt?.pptx
Farming systems analysis: what have we learnt?.pptx
 
8.Isolation of pure cultures and preservation of cultures.pdf
8.Isolation of pure cultures and preservation of cultures.pdf8.Isolation of pure cultures and preservation of cultures.pdf
8.Isolation of pure cultures and preservation of cultures.pdf
 
Authoring a personal GPT for your research and practice: How we created the Q...
Authoring a personal GPT for your research and practice: How we created the Q...Authoring a personal GPT for your research and practice: How we created the Q...
Authoring a personal GPT for your research and practice: How we created the Q...
 
Mending Clothing to Support Sustainable Fashion_CIMaR 2024.pdf
Mending Clothing to Support Sustainable Fashion_CIMaR 2024.pdfMending Clothing to Support Sustainable Fashion_CIMaR 2024.pdf
Mending Clothing to Support Sustainable Fashion_CIMaR 2024.pdf
 
EWOCS-I: The catalog of X-ray sources in Westerlund 1 from the Extended Weste...
EWOCS-I: The catalog of X-ray sources in Westerlund 1 from the Extended Weste...EWOCS-I: The catalog of X-ray sources in Westerlund 1 from the Extended Weste...
EWOCS-I: The catalog of X-ray sources in Westerlund 1 from the Extended Weste...
 
The binding of cosmological structures by massless topological defects
The binding of cosmological structures by massless topological defectsThe binding of cosmological structures by massless topological defects
The binding of cosmological structures by massless topological defects
 
AJAY KUMAR NIET GreNo Guava Project File.pdf
AJAY KUMAR NIET GreNo Guava Project File.pdfAJAY KUMAR NIET GreNo Guava Project File.pdf
AJAY KUMAR NIET GreNo Guava Project File.pdf
 
11.1 Role of physical biological in deterioration of grains.pdf
11.1 Role of physical biological in deterioration of grains.pdf11.1 Role of physical biological in deterioration of grains.pdf
11.1 Role of physical biological in deterioration of grains.pdf
 
(June 12, 2024) Webinar: Development of PET theranostics targeting the molecu...
(June 12, 2024) Webinar: Development of PET theranostics targeting the molecu...(June 12, 2024) Webinar: Development of PET theranostics targeting the molecu...
(June 12, 2024) Webinar: Development of PET theranostics targeting the molecu...
 
Micronuclei test.M.sc.zoology.fisheries.
Micronuclei test.M.sc.zoology.fisheries.Micronuclei test.M.sc.zoology.fisheries.
Micronuclei test.M.sc.zoology.fisheries.
 
HOW DO ORGANISMS REPRODUCE?reproduction part 1
HOW DO ORGANISMS REPRODUCE?reproduction part 1HOW DO ORGANISMS REPRODUCE?reproduction part 1
HOW DO ORGANISMS REPRODUCE?reproduction part 1
 
Sexuality - Issues, Attitude and Behaviour - Applied Social Psychology - Psyc...
Sexuality - Issues, Attitude and Behaviour - Applied Social Psychology - Psyc...Sexuality - Issues, Attitude and Behaviour - Applied Social Psychology - Psyc...
Sexuality - Issues, Attitude and Behaviour - Applied Social Psychology - Psyc...
 

Hard times to come

  • 1. Hard times to come. There are not simple groups of order 2016. [Scott, Ex.10.7.13.] Proof. Let G be a simple groupof order 2016. Along the lines of the analogue statement for 1008, 10.7.5. in Scott. Let n7 be the number of 7- Sylow subgroups P. One has that n7=8,36 or 288 by Sylow (must divide 288 and congruent to 1 mod 7). If n7=8 then 3 divides |C(P)| so there is an element of order 21 which is impossible in the symmetric group S8.
  • 2. Let n7=36, |N(P)|=56, N/C embeds into Aut(P) of order 6 hence |C(P)|=28. There is an element of order 2 in C(P) hence also an element x in C(P) of order 14. By 10.2.10 in the faithful representation on N(P) of degree 36, x^2 is of cycle type 1-7-7-7-7-7 so x has type 1-14-14-7 and Ch(x^7)=8. If y is in N(P) - C(P) then by 10.2.11 Ch(y)<=6 and x and y are not conjugates. We conclude that all conjugates by elements in N(P) of involutions in C(P) remain in C(P).
  • 3. Let a be an involution in C(P) and denote by f(a) the order of Cl_N(P)(a). Appplying 10.7.4, |Cl_G(a)|=36*f(a)/8 hence f(a) must be even. A group of order 28 is either abelian of type C28 or C2xC2xC7, or nonabelian either dihedral or the extension of C14 by C4 with amalgamation. C(P) must be abelian as P is central, which is the case neither in D14 nor in the extension of C14 by C4 with amalgamation. If C(P) is Abelian of type C28 then there is only one involution which is impossible. If C(P) is Abelian of type C2xC2xC7 then there are 3 involutions of which necessarily at least one is central in N(P) as N/C is of order 2, which is again impossible.
  • 4. There remained the case n7=288. In this case G is Frobenius. Indeed, P is such that P ∩ P^g is the identity subgroup for every g in G − P. Then also the Frobenius kernel of order 288 is nilpotent, and both Sylow for 2,3 are also normal. The proof is complete. In spite of this uneasy fact, prosperous new year to all at LinkedIn and the StackExchange.